He's Dead, Jim
The message of the veto by Belgium et al is this: the alliance is now a la carte; it is up to us to decide whether a threatened member shall be protected or not. Indeed, we will veto even the planning for such a contingency under Article 4. This clause of the Nato treaty allows a member state to ask for consultations on what the alliance might do if an impending threat actually does materialise.
Not such a big thing, you might think - all we're talking about is the little matter of dispatching a handful of Patriot missiles to deter Saddam Hussein from attacking Turkey. Such a move would prejudice nothing; it would merely send a sorely needed message to Baghdad to the effect: "Don't even go there."
The implied signal from Brussels now reads: the coalition that so effectively deterred a Soviet attack for 50 years has now become a contingency; we may help each other, and then we may not because we have other fish to fry.
Furthermore, it's not like Turkey was asking to borrow a Panzer division or two so they could blitzkrieg into Mosul and take all the oil. Nope. All Turkey asked for was some defensive weaopns -- anti-aircraft and Patriot anti-missile missiles.
In other words, Turkey asked merely that its NATO allies lend it equipment that has no utility unless Turkey is attacked. In other other words, Turkey was asking that NATO fulfill its promise "that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all."
An alliance which can't even consider the possibility of protecting a threatened member isn't worthy of the name. I'm not yet ready to kill NATO, but my disposition to create a new alliance of real allies is certainly reinforced.